From f8154a63c091e13cc591d277b854ea3d45d91fc2 Mon Sep 17 00:00:00 2001
From: mycroft <mycroft@NetBSD.org>
Date: Sun, 9 Jan 1994 14:59:42 +0000
Subject: [PATCH] Don't bogusly save the supervisor stack on signals.  Correct
 PSL checks.  Fix some return values from sigreturn().

---
 sys/arch/i386/i386/machdep.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/sys/arch/i386/i386/machdep.c b/sys/arch/i386/i386/machdep.c
index a2a7682cfdeb..0bf4e333f127 100644
--- a/sys/arch/i386/i386/machdep.c
+++ b/sys/arch/i386/i386/machdep.c
@@ -452,7 +452,6 @@ sendsig(catcher, sig, mask, code)
 	fp->sf_sc.sc_mask = mask;
 	fp->sf_sc.sc_ebp = tf->tf_ebp;
 	fp->sf_sc.sc_esp = tf->tf_esp;
-	fp->sf_sc.sc_isp = tf->tf_isp;
 	fp->sf_sc.sc_eip = tf->tf_eip;
 	fp->sf_sc.sc_efl = tf->tf_eflags;
 	fp->sf_sc.sc_eax = tf->tf_eax;
@@ -500,6 +499,7 @@ sigreturn(p, uap, retval)
 	register struct sigcontext *scp;
 	register struct sigframe *fp;
 	register struct trapframe *tf;
+	int eflags;
 
 	tf = (struct trapframe *)p->p_regs;
 
@@ -513,19 +513,18 @@ sigreturn(p, uap, retval)
 	     ((caddr_t)scp - offsetof(struct sigframe, sf_sc));
 
 	if (useracc((caddr_t)fp, sizeof(*fp), 0) == 0)
-		return(EINVAL);
+		return(EFAULT);
 
 	if (useracc((caddr_t)scp, sizeof(*scp), 0) == 0)
+		return(EFAULT);
+
+	eflags = scp->sc_efl;
+	if ((eflags & PSL_USERCLR) != 0 ||
+	    (eflags & PSL_USERSET) != PSL_USERSET ||
+	    (eflags & PSL_IOPL) > (tf->tf_eflags & PSL_IOPL))
 		return(EINVAL);
 
-	/* make sure they aren't trying to do anything funny */
-	if ((scp->sc_ps & PSL_MBZ) != 0 || (scp->sc_ps & PSL_MBO) != PSL_MBO)
-		return(EINVAL);
-
-	/* compare IOPL; we can't insist that it's always 3 or the X server
-	   will fail */
-	if ((tf->tf_eflags & PSL_IOPL) < (scp->sc_efl & PSL_IOPL))
-		return(EINVAL);
+	/* XXXXXX NEED TO VALIDATE SEGMENT REGISTERS */
 
 	p->p_sigacts->ps_onstack = scp->sc_onstack & 01;
 	p->p_sigmask = scp->sc_mask &~
@@ -536,9 +535,8 @@ sigreturn(p, uap, retval)
 	 */
 	tf->tf_ebp = scp->sc_ebp;
 	tf->tf_esp = scp->sc_esp;
-	tf->tf_isp = scp->sc_isp;
 	tf->tf_eip = scp->sc_eip;
-	tf->tf_eflags = scp->sc_efl;
+	tf->tf_eflags = eflags;
 	tf->tf_eax = scp->sc_eax;
 	tf->tf_ebx = scp->sc_ebx;
 	tf->tf_ecx = scp->sc_ecx;
@@ -549,6 +547,7 @@ sigreturn(p, uap, retval)
 	tf->tf_ds = scp->sc_ds;
 	tf->tf_es = scp->sc_es;
 	tf->tf_ss = scp->sc_ss;
+
 	return(EJUSTRETURN);
 }